Re: [PATCH v20 09/41] ASoC: Add SOC USB APIs for adding an USB backend

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

Hi Amadeusz,

On 4/26/2024 6:25 AM, Amadeusz Sławiński wrote:
> On 4/25/2024 11:50 PM, Wesley Cheng wrote:
> > Some platforms may have support for offloading USB audio devices to a
> > dedicated audio DSP.  Introduce a set of APIs that allow for 
> > management of
> > USB sound card and PCM devices enumerated by the USB SND class driver.
> > This allows for the ASoC components to be aware of what USB devices are
> > available for offloading.
> >
> > Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
> > ---
>
> (...)
>
> > +const char *snd_soc_usb_get_components_tag(bool playback)
> > +{
> > +    if (playback)
> > +        return "usbplybkoffld: 1";
> > +    else
> > +        return "usbcapoffld: 1";
> > +}
> > +EXPORT_SYMBOL_GPL(snd_soc_usb_get_components_tag);
>
> Is this used to expose some information to userspace?
> Can those be some more readable strings if so, like:
> usbplaybackoffload, usbcaptureoffload

Sure we can make it a bit more complete.  Was trying to keep it short, 
but if the intention isn't clear on the tag, then we can keep the full form.

> (...)
>
> > +
> > +    node = snd_soc_find_phandle(usbdev);
> > +    if (IS_ERR(node))
> > +        return -ENODEV;
> > +
> > +    ctx = snd_soc_find_usb_ctx(node);
> > +    of_node_put(node);
> > +    if (!ctx)
> > +        return -ENODEV;
>
> Perhaps introduce some helper function, you do this 
> snd_soc_find_phandle() followed by snd_soc_find_usb_ctx() in few places...

Will do.  Will make a helper and replace instances with this.

Thanks
Wesley Cheng